Many documents are written collaboratively. People often collaborate on documents by e-mailing drafts of the document to each other. One person creates the initial document and e-mails it to the other collaborators. When a collaborator receives the document, the collaborator opens the document with the appropriate program (e.g., word processor, spreadsheet, etc.) and makes changes. That collaborator then re-attaches the revised document to an e-mail and sends it to the other collaborators. When other collaborators receive the revisions, they may make changes to the document and pass those changes on to others in a like manner. This process is unwieldy, because it involves several distinct actions to open and edit an e-mail attachment, and to reattach the edited version to another e-mail.
Some on-line services have begun to offer on-line document storage and editing. Such services provide users with a document repository that may be used to store documents. These services often provide browser-based document-processing software, such as word processors, spreadsheets, Portable Document Format (PDF) readers, etc., that run in browsers. Users can view and edit the documents in the browser using the browser-based software, and can save changes to the documents to the document repository.
However, there are certain aspects to on-line document services that can make these services cumbersome to use for collaboration. The process of opening and editing an e-mailed document, and then replying to the e-mail with changes, can be awkward in these systems. Additionally, the access control systems in on-line document services make it difficult to create a document that is accessible to the recipients of an e-mail, but not to the public at large.